[SPARC32]: Make flush_tlb_kernel_range() an inline function.

This avoids unused variable warnings in places like mm/vmalloc.c:

mm/vmalloc.c: In function ‘unmap_kernel_range’:
mm/vmalloc.c:75: warning: unused variable ‘start’

caused by it previously being a macro.

Signed-off-by: David S. Miller <davem@davemloft.net>